The "Laguna Beach" alum confirmed on Monday that she and the
"We're at it again! Thrilled to announce baby number 3 is on the way! The Cutler crew keeps on growin'!" the 28-year-old wrote, posting a portrait of herself making a heart on her belly.
Her two sons -- Camden Jack, 2, and Jaxon Wyatt, 1 -- are also in the shot, riding a little red wagon behind their expectant mama.
The jewelry and shoe designer wed the NFL star in Nashville in June 2013 after an on-and-off engagement.
No word yet on baby No. 3's ETA, and reps for Cavallari did not immediately respond to requests for comment.